There's a lot of paywall going on re: anandamide concentrations. Will have to go get some login credentials to view them, but absent FAAH inhibitors it looks like staggering amounts of chocolate would have to be consumed to produce an appreciable effect. I couldn't find any good sources for palmitoylethanolamide in cacao - do you remember where you came across that? Or were you maybe thinking of just general FAAH-inhibiting flavonoids?
Despite the fact that
N-acylethanolamines (NAEs) (
Table 1) from plants do not interact with CB receptors (plants do not generally produce arachidonic acid, which is the acyl scaffold favoured for CB interaction) they have been shown to inhibit FAAH, thus leading to an increase in endocannabinoid tone.
N-linoleoylethanolamide and
N-oleoylethanolamide, which are found not only in chocolate (
Theobroma cacao L.) but also other plants (
Di Marzo et al., 1998), and the widespread NAE palmitoylethanolamide, inhibit anandamide breakdown (
Maurelli et al., 1995;
Di Tomaso et al., 1996). Certain
N-alkylamides (alkamides) from
Echinacea spp. (
Table 2) have been shown to interact functionally with the human CB2 receptor with low nM to µM
Ki values (
Gertsch et al., 2006). These
N-isobutylamides selectively act at the CB2 receptor over the CB1 receptor, leading to an increase in intracellular calcium which could be blocked by the selective CB2 receptor inverse agonist SR144528, but they do not modulate the Gαi signalling pathway. Intriguingly, CB2 receptor-binding
N-alkylamides show similar anti-inflammatory effects as anandamide (e.g. inhibition of TNF-α) at low nM concentrations (
Raduner et al., 2006). Certain
Echinacea N-alkylamides inhibit anandamide reuptake
in vitro (
Chicca et al., 2009). Like anandamide,
N-alkylamides also target PPAR-gamma (
Spelman et al., 2009). Different
Echinacea N-isobutylamides are orally bioavailable resulting in nM plasma levels in humans (
Woelkart et al., 2008). The polyacetylenic polyyne falcarinol, which is found in different plants of the Apiaceae family (e.g. in carrots) shows significant binding interactions with both cannabinoid receptors, but appears to selectively undergo an alkylation reaction with the CB1 receptor (
Ki value <1 µM), leading to relatively potent inverse agonistic and pro-inflammatory effects in human skin (
Leonti et al., 2010). Finally, it has been proposed that certain dietary fatty acids, which can also be found in plants, can modulate the ECS by influencing the availability of phospholipid biosynthetic precursors of endocannabinoids (
Banni and Di Marzo, 2009).